This invention relates generally to apparatus for storing perishable goods and, in particular, for storing perishable goods at a desired temperature for preserving the goods over an extended period of time.
As set forth in U.S. Pat. No. 6,012,384 to Badalament, et al., a mobile container for shipping perishable goods such as fruits and vegetables has been devised which helps to maintain the goods at or close to a desired temperature. Included in these goods are fruits and vegetables that are undergoing an exothermic ripening process which makes control of the internal container temperature difficult to maintain. The outside temperature of the surrounding ambient can also have a pronounced effect on the internal temperature of the container which again adversely effects the ripening process.
The container disclosed in the Badalament, et al. patent is an elongated sealed enclosure mounted on wheels so that the container can be transported by various means from place to place. A refrigeration unit is mounted on the front wall of the container and is arranged to deliver conditioned air at a desired temperature to an air mixing chamber that is located in the container adjacent to the front wall. The cargo is stacked in two rows extending along the length of the container to establish a pair of air delivery plenums extending back from the mixing chamber to the rear wall of the container along the side walls of the container. A central return plenum is similarly provided between the two rows of stacked goods. One or more fans are mounted in the mixing chamber which are arranged to pump conditioned air from the mixing chamber into the two delivery plenum. The conditioned air is pumped through the goods and then back into the mixing chamber via the return plenum.
The Badalament container represents an improvement in the art in that it enables the goods in transit to be exposed directly to conditioned air. However, as noted above, the blowers employed in the system are located in the mixing chamber and the conditioned air leaving the evaporator is warmed by the heat generated by the blower motors before the conditioned air reaches the goods that are to be cooled. This uncontrolled heating of the conditioned air prior to the conditioned air reaching the goods can have an adverse effect on the ripening process. In addition, the conditioned air is moved along the side walls of the container before reaching the goods. Depending on the ambient temperature surrounding the container, the conditioned air can be either heated or cooled as it moves over the side wall surfaces, again adversely effecting the ripening process. It should be further noted that the Badalament mixing chamber is located on the low pressure side of the container flow system which, under certain conditions, does not provide for the most efficient flow of air through the system.
It is, therefore, a primary object of the present invention to improve containers for storing and/or transporting perishable goods.
It is a further object of the present invention to provide an improved system for moving conditioned air through a container for storing perishable goods.
It is a still further object of the present invention to improve the mixing of conditioned air with return air in a container in order to maintain stored perishable produce at a desired temperature for controlled ripening of the produce.
Another object of the present invention is to improve the control of air temperature within a container in which perishable goods are stored.
Yet another object of the present invention is to reduce the number of uncontrollable variables that might adversely affect the air temperature within a container for storing and preserving goods.
These and other objects of the invention are attained in a sealed container that is coupled to a refrigeration unit for delivering conditioned air to a mixing plenum. The plenum is located within the container along the container""s front wall. A load of perishable goods is stored in air penetratable bins or packages that are stacked in two spaced-apart rows extending from the mixing plenum rearwardly toward the back of the container. The stacks are arranged to form a central air supply duct that communicates with the mixing plenum through means of a supply air opening and a pair of return air ducts that extend along the two side walls of the container and which communicate with the mixing plenum through return air openings. Blower units are mounted in each return air duct and are arranged to draw air through the load from the supply air duct and deliver the air into the mixing plenum at an increased pressure. The low pattern that is established through the container is such that supply air from the mixing plenum reaches the goods before it moves over the side walls of the container and the blower motors. As a result, the temperature of the goods undergoing ripening can be closely controlled.